Film gate



July 6, 1937.. R P. MAY 2,085,919

FILM GATE Original Filed Nov. 3, 1931 5 Sheets-Sheet l INVENTOR RUJSELL P. MAY BY K ATTORNEY R. F. MAY

FILM GATE July 6, 1937.

5 Sheets-Shea?I 2 Original Filed Nov. 3, 193.1

INVENTOR RUSSELL P. MAY 'BY Wwf ATTORNEY July 6, 1937. R, P MAY ZSQQ FILM GATE Original Filed Nov. 5, 1931 5 Sheets-Sheet 3 INVENTOR RUSSELL P MAY ATTORNEY Jlly 6, R P MAY FILM GATE Original Filed Nov. 5, 1931 5 Sheets-Sheet 4 HNVENTOR RUSSELL P. MAY

BAY/@ZW ATTORNEY July e, 1937. R. P; MAY 2,085,919

FILM`GATE Original Filed Nov. 3, 1931 5 Sheets-Sheet 5 Zmventor Gttorneg Patented July 6,- 1937 UNITED STATES PATENT FFICE FILM GATE of Delaware Original application November 3, 1931, Serial No. 572,804, now Patent No. 2,003,381, dated June 4, 1935.

Divided and this application December 4, 1933, Serial No. I100,808

1 Claim.

The present invention relates to portable talking motion picture apparatus particularly adapted to home and educational use, and is a division of my Patent No. 2,003,381, issued June 4, 1935. It involves the provision of an improved projector, an improved sound reproducer, and an improved amplifier, al1 built into a single, lightweight,- inexpensive unit tted within a soundproof carrying case.

One object of the invention is to provide an improved talking motion picture apparatus adapted to use 16 mm. iilm which carries thereon a soundtrack of one of the usual types in commerciaiuse.

Another object of the invention is to provide such an apparatus which is capable of high quality sound reproduction from such a film.

Another object of the invention is to provide such an apparatus which requires a minimum power to operate it and which can therefore be operated from any ordinary household power supply.

Another object of the invention is the provision of an improved iilm gate which permits the .dim to be driven from one row of sprocket holes only without icker at the aperture and without the lm tending to run off to yone side or the other.v

Other and ancillary objects of the invention will be apparent from a reading of the following speciilcation in connection with the accompanying drawings and its scope will be pointed out in the appended drawings wherein: f

Referring to the drawings:

Fig. 1 is a side view of the projector as mountedin the carrying case and with the carrying case open for threading-of the projector.

Fig. 2 is an enlarged view of the film gate.

Fig. 3 is a front view of the illm gate showing a modified form of the springs.

Fig. 4 shows a modiiled form of nlm gate.

Figs. 5, 6, and '7 show details thereof; and

Fig. 8 is a transverse section through the gate shown in Fig. 4.

'I'he nlm F with which this projector is intended to co-operate is of the conventional 16 mm. width and is provided with pictures of exactly A the same size as are ordinarily used on 16 mm.

made to run at a speed of 24 frames or pictures (Cl. 88-17i per second -which is the usual speed in talking motion pictures instead of 16 pictures per second which has heretofore been usual in 16 mm. iilms. The reason for this is that such pictures can be properly printed by projection when desired from standard theatre lms or the equivalent without requiring that a special negative be taken and a special soundtrack be made to be capable of reproduction in this apparatus.

The projector as shown in Fig. l is housed within a carrying case i0. This carrying case as indicated at ii is lined with appropriate sound-absorblng material to absorb any noise which might be produced by the projector mechanism, the motor, or the fluttering of the lm in order to avoid any disturbance of the audience, and is provided with suitable apertures or the lens as at i2, for the entrance and exit of wires as at i3, and :for the entrance and exit of the nlm as at il.

After the film F has been threaded with the A case open, the case is closed and remains in closed position during operation, thereby retaining within the case not only the noise of the projector but also any stray light which may escape from the lamphouse.

One form of my improved film gate is shown in Figs. 1, 2, and 3. 1n this form of gate there is a plate di? attached to the motor housing in front oi the optical system and shutter. and this plate has an appropriately surfaced channel in it to receive the illm. Against this plate bears the pressure shoe 6U which is in the form of a pressed metal plate having appropriately formed contact surfaces for the nlm and'having outwardly extending ears at the top and bottom, as shown, by which it may be grasped to open it. This gate is heldin closed position by the springs BI against the'pressure of which it may be opened by grasping the ears above referred to and the elongated apertures in the sides of the gate vwhich engage the pins 62 may then be slid down over the pins 62, retaining the gate in open position.

As shown in Figs. 1 and 2, the springs 6l are of the helical compression type. In Fig. 3 is shown a more compact spring consisting of the coil type mounted around the rods 62 thereby providing a construction avoiding the projecting springs shown in Figs. 1 and 2.

A modified form of gate is shown in Fig. i and this particular form of gate is found to be peculiarly eifective when the film F is drawn by traction of the intermittent feed 42 on sprocket holes on one edge of the film only.

In this gate a backing `plate 59 is provided as in the gate previously referred to, but the llm is pressed toward this by a linear shoe 10. This shoe is provided with ears 1I which serve the same function as the ears above referred to and these ears are each provided with a notch 'l2 in their lower edges whereby the pressure shoe may be maintained in open position by drawing it outwardly and hooking these notches over the plates 13, which also serve as spring-retaining members. The opposite edge of the lm is prevented from uttering by a guide I4 which extends the entire length of the gate but which, instead of belng pressed firmly against the film by springs, is set at such spacing from the guide on the 15 backing plate that the iilm can move freely therebetween. This avoids producing any tension on the edge of the lm which is not drawn by the intermittent and atthe same time, due to the small clearance (which may be oi.' the order of two one-thousandths of an inch) the guide acting in co-operation with the pressure vshoe at the other edge of the aperture. prevents any flutter of the film at the projection aperture.

I claim:

A film gate comprising means for maintaining one edge of the film passing therethrough and fed at that edge only under tension, and guide means on the'other edge of the film to minimize utter, said guide means so spaced from the backing plate that the film can move freely therebetween.

RUSSELL P. MAY. 

